PM2.5 vs AQI on Temtop S1-UP What Is the Difference Malaysia

PM2.5 vs AQI on Temtop S1-UP What Is the Difference Malaysia

The Temtop S1-UP displays both PM2.5 and AQI.

But what is the difference?

Is PM2.5 the actual particle concentration?

Is AQI another type of sensor?

Why do the two readings change together?

Which one should you look at when checking Malaysian haze?

The simple answer is:

PM2.5 is a measured particle concentration.

AQI is an index used to communicate the significance of an air-quality condition.

They are related, but they are not the same type of value.

Understanding this difference helps users interpret the S1-UP more correctly.

What Does the Temtop S1-UP Measure?

The S1-UP monitors:

PM2.5

AQI

Temperature

Relative humidity

It is suitable for general monitoring in:

Homes.

Bedrooms.

Offices.

Classrooms.

Tuition centres.

Clinics.

Retail shops.

Air-conditioned rooms.

The S1-UP provides direct on-screen readings without requiring a mobile App for basic monitoring.

What Is PM2.5?

PM2.5 refers to fine airborne particles with a diameter of 2.5 micrometres or smaller.

The PM2.5 reading represents the concentration of these particles in the surrounding air.

PM2.5 may come from:

Regional haze.

Road traffic.

Open burning.

Industrial emissions.

Construction activity.

Cooking smoke.

Cigarette smoke.

Burning incense.

Dust-producing indoor activities.

The S1-UP detects the particle condition around the instrument.

What Unit Is Used for PM2.5?

PM2.5 concentration is commonly shown in:

Micrograms per cubic metre — µg/m³

This represents the mass concentration of fine particles within a volume of air.

A PM2.5 value is therefore a concentration measurement.

It should not be confused with the AQI number.

What Is AQI?

AQI means:

Air Quality Index

An AQI converts pollutant information into an index intended to make air-quality conditions easier to communicate.

Instead of only displaying a technical concentration, an AQI may provide a more understandable indication of the air-quality category.

However, AQI systems can vary according to:

Country.

Authority.

Pollutant.

Averaging period.

Calculation method.

Breakpoints.

For this reason, AQI values from different sources should not always be expected to match exactly.

Is AQI Measured Directly?

Not in the same way as PM2.5 concentration.

The monitor detects particle information and uses its programmed method to present an AQI indication.

AQI is therefore an interpreted index rather than a separate physical particle type.

This means:

PM2.5 is not AQI.

AQI is not another pollutant.

They are two ways of presenting related air-quality information.

Why Do PM2.5 and AQI Change Together?

If the S1-UP bases its displayed AQI on PM2.5, an increase in PM2.5 may cause the AQI indication to increase.

A decrease in PM2.5 may cause the AQI indication to improve.

For example:

Cooking starts.

PM2.5 increases.

The displayed AQI may also worsen.

The air purifier starts.

PM2.5 decreases.

The displayed AQI may improve.

The two readings are connected, but they are not numerically interchangeable.

Why Is PM2.5 Not the Same Number as AQI?

They use different scales and meanings.

PM2.5 is a concentration.

AQI is an index.

For example, a PM2.5 reading should not be interpreted as though the same numerical value automatically equals the same AQI.

The conversion depends on the AQI method used by the monitor or information source.

Do not manually assume:

PM2.5 value = AQI value

without checking the applicable calculation method.

Which Reading Should You Watch?

It depends on your purpose.

Look at PM2.5 When You Want To:

Compare particle concentration before and after operating an air purifier.

Compare two rooms.

Observe whether particles increase during cooking.

Check whether PM2.5 rises when a window opens.

Record a numerical particle trend.

Look at AQI When You Want To:

Understand the monitor’s general air-quality indication.

Communicate the condition more simply.

See whether the indicated air-quality category is improving or worsening.

For practical monitoring, it is useful to observe both.

Which Reading Is Better for Air Purifier Testing?

Focus primarily on PM2.5 concentration.

A simple air-purifier comparison may include:

Record the initial PM2.5.

Switch on the purifier.

Keep the monitor in one position.

Record the purifier speed.

Keep doors and windows consistent.

Observe the PM2.5 trend.

The AQI indication can provide supporting information, but PM2.5 gives a direct numerical concentration for the comparison.

Which Reading Is Better During Malaysian Haze?

Both are useful.

PM2.5 provides a particle-concentration value.

AQI provides a general interpreted indication.

During haze, users may want to know:

Is indoor PM2.5 increasing?

Is the indoor AQI indication worsening?

Does closing the window reduce PM2.5?

Does the air purifier improve the condition?

The S1-UP helps answer these questions inside the monitored room.

Is Outdoor AQI the Same as S1-UP AQI?

Not necessarily.

An outdoor AQI report may be based on:

A different monitoring station.

A different location.

A different averaging period.

A different pollutant.

A different calculation method.

Outdoor environmental conditions.

The S1-UP measures the air around the instrument indoors.

Therefore, differences can occur.

Do not assume the S1-UP is faulty simply because it does not match an outdoor AQI App exactly.

Malaysian API vs AQI on a Monitor

Malaysian users may see air-pollution information presented through official outdoor reporting systems.

A consumer monitor may use a different index method or pollutant basis.

For this reason:

Do not assume that every index number from every device, App or authority is directly interchangeable.

When comparing indoor changes with one instrument, keep the method consistent.

Use the S1-UP to observe what happens in the room over time rather than expecting it to duplicate a distant outdoor station.

Why Can Outdoor AQI Be High but Indoor PM2.5 Be Lower?

Possible reasons include:

Windows are closed.

External doors remain closed.

An air purifier is operating.

The building has effective particle filtration.

The room is far from the external entrance.

Outdoor particles have limited entry.

The S1-UP provides information about the indoor location, which may be different from the outdoor environment.

Why Can Indoor PM2.5 Be Higher Than Outdoor Information?

Possible indoor sources include:

Cooking.

Smoking.

Burning incense.

Cleaning.

Candles.

Dust disturbance.

Particles entering from another room.

A local indoor activity may cause the S1-UP reading to increase even when the wider outdoor condition appears better.

Can PM2.5 Increase in an Air-Conditioned Room?

Yes.

Air conditioning mainly controls temperature.

A cool room may still experience changing PM2.5 because of:

Outdoor haze.

Door movement.

Cooking smoke.

Smoking.

Dust disturbance.

Insufficient filtration.

Particles entering from another area.

Cool air does not automatically mean low PM2.5.

Can AQI Improve While Temperature Stays the Same?

Yes.

AQI and temperature describe different conditions.

An air purifier may reduce PM2.5 and improve the AQI indication without significantly changing the room temperature.

Likewise, an air conditioner may reduce temperature without improving PM2.5 or AQI.

This is why the S1-UP displays the parameters separately.

Can Humidity Affect How the Room Feels?

Yes.

Humidity influences comfort and may change with:

Weather.

Air conditioning.

Occupancy.

Open windows.

Humidifiers.

Nearby moisture.

However, humidity is not the same as PM2.5 or AQI.

A room may feel humid while particle levels are low.

It may also feel dry while PM2.5 is elevated.

Does a Low AQI Mean CO2 Is Low?

No.

The S1-UP does not measure CO2.

A room may have:

Low PM2.5.

A favourable AQI indication.

Increasing CO2.

This may occur in a closed room with an operating air purifier and several occupants.

AQI based on particle information should not be used as a substitute for CO2 monitoring.

Does a Low PM2.5 Reading Mean No Formaldehyde?

No.

The S1-UP does not measure:

Formaldehyde.

HCHO.

TVOC.

A low PM2.5 value does not confirm that chemical pollutants are absent.

For renovation or new-furniture concerns, choose an instrument with the appropriate measurement capability.

Does AQI Include Every Indoor Pollutant?

Not necessarily.

The displayed AQI should be interpreted according to the monitor’s design and pollutant basis.

The S1-UP is focused on PM2.5-related air-quality monitoring.

Do not assume that its AQI represents:

CO2.

TVOC.

Formaldehyde.

Carbon monoxide.

Combustible gas.

Every possible indoor pollutant.

Always confirm what the instrument actually measures.

PM2.5 vs PM10

PM2.5 refers to smaller fine particles.

PM10 includes a broader larger-particle category.

The S1-UP focuses on PM2.5.

It does not display PM10.

If your application specifically requires both PM2.5 and PM10, consider an appropriate particle monitor such as the Temtop P600.

Using PM2.5 for Room-to-Room Comparison

One S1-UP may be moved between:

Bedroom.

Living room.

Home office.

Meeting room.

Classroom.

When comparing rooms:

Use a similar monitor position.

Keep away from direct airflow.

Record doors and windows.

Record air-purifier operation.

Allow the reading to stabilise.

Use the PM2.5 concentration for a more direct numerical comparison.

Using AQI for Simple Communication

AQI can help make the displayed condition easier to communicate.

For example, a facility team may explain whether the monitor’s indication has:

Improved.

Worsened.

Remained similar.

However, if formal technical records are required, the team should document the measured parameters, method, location and time rather than relying only on a general category.

Why Does AQI Change Suddenly?

Possible reasons include:

PM2.5 crossing an index breakpoint.

Cooking beginning.

A door opening.

The purifier changing speed.

Outdoor haze entering.

The monitor being moved.

Airflow changing.

An AQI category may change even when the concentration difference appears modest.

Look at the PM2.5 concentration and room conditions together.

Why Does PM2.5 Change but AQI Look Similar?

Possible explanations include:

The PM2.5 change remains within the same AQI category.

The index display updates according to its programmed method.

The difference is too small to create a visible category change.

The monitor is in a different operating mode.

Observe both the numerical PM2.5 value and AQI indication.

Why Do Two Monitors Show Different AQI?

Different monitors may use:

Different sensors.

Different algorithms.

Different averaging methods.

Different AQI standards.

Different update behaviour.

Different positions.

Before comparing:

Confirm both instruments are measuring the same pollutant.

Place them together.

Use the same room conditions.

Allow readings to stabilise.

Check whether they use the same AQI basis.

A different AQI value does not automatically prove that one instrument is faulty.

Why Does S1-UP Not Match a Weather App?

A weather App may use data from an outdoor monitoring station.

The S1-UP measures the air at its indoor position.

Differences may be caused by:

Distance.

Indoor filtration.

Window condition.

Building leakage.

Local indoor sources.

Different averaging periods.

Different AQI methods.

Use each source for its intended purpose.

The outdoor App describes wider outdoor conditions.

The S1-UP describes the air around the indoor monitor.

How to Monitor PM2.5 During Haze

A practical procedure may include:

Place the S1-UP in a representative indoor position.

Record PM2.5 and AQI.

Record windows and doors.

Record air-purifier status.

Keep the monitor in one position.

Observe the trend.

Avoid placing it directly beside a window or purifier outlet.

How to Monitor an Air Purifier

Record:

PM2.5 before purifier operation.

The displayed AQI indication.

Purifier speed.

Room conditions.

Time.

Keep the S1-UP away from direct clean-air discharge.

Observe whether PM2.5 decreases and the AQI indication improves.

Do not judge the purifier from one momentary value.

ECO Mode or A Mode for PM2.5 and AQI?

ECO Mode

Choose ECO Mode for longer general monitoring.

According to Temtop, standby duration may reach approximately 60 days, depending on use and battery condition.

A Mode

Choose A Mode for more immediate active checking.

According to Temtop, standby duration may reach approximately 20 days, depending on use and battery condition.

For air-purifier or window comparisons, A Mode may be more suitable.

For ongoing room observation, ECO Mode may be preferred.

Common PM2.5 and AQI Interpretation Mistakes

Mistake 1: Treating PM2.5 and AQI as the Same Number

One is a concentration and the other is an index.

Mistake 2: Comparing Indoor AQI Directly with Every Outdoor App

The source, method and environment may differ.

Mistake 3: Assuming AQI Includes CO2

The S1-UP does not measure CO2.

Mistake 4: Assuming Low PM2.5 Means No Formaldehyde

Different pollutants require different sensors.

Mistake 5: Ignoring Monitor Placement

A reading beside a window or purifier outlet may not represent the room.

Mistake 6: Judging Air Quality from One Reading

Observe trends and room conditions.

Mistake 7: Assuming Cool Air Means Low PM2.5

Temperature and particles are different measurements.

Which Value Should a Home User Record?

For a practical home monitoring log, record:

PM2.5 concentration

AQI indication

Temperature

Humidity

Time

Room

Window condition

Door condition

Air purifier status

Relevant activity

This provides much more useful context than recording only one number.

PM2.5 vs AQI Final Explanation

The easiest way to remember the difference is:

PM2.5 tells you the concentration of fine particles.

AQI translates air-quality information into an index for easier interpretation.

Use PM2.5 when you want to:

Compare particle concentrations.

Check an air purifier.

Compare rooms.

Monitor haze entry.

Use AQI when you want to:

Understand the general indicated condition.

Communicate whether air quality appears better or worse.

Always interpret the readings together with:

Monitor placement.

Room activity.

Doors and windows.

Air purifier operation.

The selected operating mode.

Most importantly:

The Temtop S1-UP AQI should not be treated as CO2, TVOC, formaldehyde or a measurement of every possible indoor pollutant.

Contact MTM Precision

Contact MTM Precision for Temtop S1-UP Malaysia price and quotation, or for assistance selecting Temtop monitors for PM2.5, AQI, haze, air purifiers, homes, offices and classrooms.

MTM Precision Sdn Bhd

Showroom & Service Centre:

No. 29-1 & 29-2, Jalan Bandar 18,

Pusat Bandar Puchong,

47160 Puchong, Selangor, Malaysia

Tel: 03-8080 7172

WhatsApp: +6016-660 7346

Email: mtmpre@yahoo.com

Website: www.mtmpre.com.my